Showing papers by "University of Lisbon published in 1974"
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TL;DR: An overview of hollow cathode arcs (HCA) can be found in this paper, where a historical review of HCA is presented and operating conditions for low-pressure HCA are described.
Abstract: Publisher Summary This chapter provides an overview of hollow cathode arcs (HCA). Hollow cathodes have been used for some years in different discharge devices, working under varying conditions in widely extended ranges. All of these devices have one common feature: the cathode presents a hollow cavity, enclosed or at least partially bound by walls made of conducting refractory materials kept at the cathode potential. The geometry of such cathodes is such that their open side faces the anode side of the discharge, so that the plasma existing at the interelectrode space can penetrate the hollow cathode, thus assuring a strong interaction between the plasma and the cathode internal surface. In general terms, this interaction affects an extensive area of the cathode wall; a positive space-charge sheath builds up, so that the incoming ions are strongly accelerated before neutralization upon the wall. In this chapter, historical review of HCA is presented. Working regimes of HCA are elaborated. Operating conditions for low-pressure HCA are described. Experimental results for the normal regime are presented. Theory of HCA in the N regime is also discussed.
89 citations
TL;DR: In Continental Portugal cases of candidiasis, mycetoma, aspergillosis, sporotrichosis and cryptococcosis were described in patients who had never been outside Europe; and tinea nigra, African histoplasmosis and South-American blastomycosis in individuals who live or lived in India, Africa and Brazil.
Abstract: A critical survey is made of human mycoses diagnosed in European Portugal and in the Portuguese Overseas Provinces. Dermatophyte infections and pityriasis versicolor are commom in the entire territory. The more frequently isolated dermatophytes in Continental Portugal wereTrichophyton violaceum, Microsporum canis, Trichophyton tonsurans andTrichophyton schoenleinii, in the scalp andTrichophyton rubrum, Trichophyton mentagrophytes, Trichophyton megninii andEpidermophyton floccosum in the other body sites. In the Overseas Provinces the species found in white people were very much the same, whereas in negroes mainlyMicrosporum audouinii andT. violaceum in Mozambique,M. audouinii in Angola, andTrichophyton soudanense, M. audouinii andT. rubrum in Guinea were identified.
6 citations
TL;DR: In this paper, the knowledge of precession and nutation is essential for the computation of astronomical coordinates and the comparison of values obtained at different dates, and it is therefore important to compute the nutations from the best available observations.
Abstract: It is well known that the knowledge of precession and nutation is essential for the computation of astronomical coordinates and the comparison of values obtained at different dates. It is therefore important to compute the nutations from the best available observations.